Orthodontics is a branch of dentistry concerned with the diagnosis, prevention, and treatment of tooth malocclusions and malpositions. Orthodontics is also concerned with the positioning and movement of teeth in relation to one another or to a space (e.g., open bite).

Metal and plastic are the most commonly used materials for orthodontic appliances. These instruments can move or hold teeth in place for clearances, exercises, adjustments, and observations. An "inter-arch wire" is the most common type of orthodontic appliance. This wire holds the upper jaw back, preventing it from closing as far over the lower jaw.

In most cases, people wear braces for 18 months to correct a dental problem. People may need to wear them for a longer period of time to correct a more serious problem.
Braces are typically made of metal or plastic, but depending on the severity of the problem, they can be made of a variety of materials. The material is selected based on what will be most effective in resolving the specific problem.

Because of the amount of time required to wear braces, many people struggle to find time to eat healthy foods and brush their teeth on a regular basis during that time. In some people who have chronic dry mouth due to braces, this can lead to tooth decay and cavities, as well as bad breath.

When braces are fitted, they often need to be adjusted and tightened on a regular basis in order to stay in place. It is suggested that people wear them for approximately 22 hours per day. Some people wear them during their entire waking hours, while others only wear them at night. The total time for wearing braces can vary depending on the individual's needs, but it should be noted that the more time they are worn each day, the faster results will be obtained.

Braces have been in use since 1834, with Dr. William T. Spitzer receiving the first patent in 1891. They were initially used to remove teeth from children who had overcrowding issues or misaligned teeth or jaws, but over time, these devices became popular with adults who had overcrowding problems.